1. Field of the Invention
This invention relates to a method of making an assembly including a metal tube and a surrounding body, and also to such an assembly produced by application of the method and useful, for example, as the pressure cylinder of a vehicle hydraulic system master cylinder for brake or clutch actuation, the surrounding body then being in the form of an outwardly projecting flange serving for the mounting of the assembly on a vehicle.
2. Description of the Prior Art
One conventional manner of securing a surrounding flange to a pressure cylinder is to provide the flange with an aperture of slightly smaller diameter than the cylinder external dimension at the intended flange location, and pressing the flange onto the tube at said location. Such a pressing operation can engender a large radially inward force on the cylinder wall, which sometimes results in unacceptable distortion of the cylinder bore and consequently in additional machining to correct the distortion, or scrapping of the assembly. A further disadvantage of the aforesaid conventional procedure is that, in order for the flange to have sufficient internal surface area around its bore to be afforded stable support on the cylinder, and also for it to be sufficiently substantial to withstand the pressing operation, it has been necessary for the flange to be of substantial thickness, which increases the weight of the assembly undesirably and represents additional cost.
It has been proposed to weld the flange in position in order to reduce the risk of the flange and tube becoming separated in use, but the application of welding heat to the tube is a further factor which may give rise to tube distortion.